Blower and vacuum cleaner

ABSTRACT

A blower according to an exemplary embodiment of the present disclosure includes a rotor that has a shaft disposed extending vertically, a stator positioned at an outer side of the rotor in a radial direction, a cylindrical housing extending in the axial direction and accommodating the rotor and the stator, and an impeller attached to the shaft, at an upper side from the stator. The stator includes a ring-shaped core back portion, plurality of teeth portions extending from the core back portion toward an inner side in the radial direction, an insulator that covers at least part of the teeth portions, a coil wound on each of the teeth portions via the insulator, and a flow path forming member of which at least part is positioned further at an inner side in the radial direction than the core back portion. The housing has a through hole that opens to the inner side. The flow path forming member connects part of the insulator or the coil at one side in the circumferential direction and part of the insulator or the coil at another side in the circumferential direction, and forms a flow path that passes further at an inner side in the radial direction than the core back portion. The flow path connects to the through hole of the housing.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present disclosure relates to a blower and a vacuum cleaner.

2. Description of the Related Art

There is known a blower of a vacuum cleaner, where cooling efficiency isincreased by passing exhaust air through the interior of the motor(Japanese Unexamined Patent Application Publication No. 11-148484).

SUMMARY OF THE INVENTION

However, there has been a problem in the blower disclosed in JapaneseUnexamined Patent Application Publication No. 11-148484 that turbulenceis generated in the flow of exhaust air when passing through theinterior of the motor, reducing venting efficiency.

A blower according to an exemplary embodiment of the present disclosureincludes a rotor that has a shaft disposed following a central axisextending vertically, a stator positioned at an outer side of the rotorin a radial direction, a cylindrical housing extending in the axialdirection and accommodating the rotor and the stator, and an impellerattached to the shaft, at an upper side from the stator. The statorincludes a ring-shaped core back portion, plurality of teeth portionsextending from the core back portion toward an inner side in the radialdirection, an insulator that covers at least part of the teeth portions,a coil wound on each of the teeth portions via the insulator, and a flowpath forming member of which at least part is positioned further at aninner side in the radial direction than the core back portion. Thehousing has a through hole that opens to the inner side. The flow pathforming member connects part of the insulator or the coil at one side inthe circumferential direction and part of the insulator or the coil atanother side in the circumferential direction, and forms a flow paththat passes further at an inner side in the radial direction than thecore back portion. The flow path connects to the through hole of thehousing.

The above and other elements, features, steps, characteristics andadvantages of the present disclosure will become more apparent from thefollowing detailed description of the preferred embodiments withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a blower according to thepresent embodiment.

FIG. 2 is a cross-sectional diagram illustrating a blower according toan embodiment.

FIG. 3 is a disassembled perspective view of the blower according to theembodiment.

FIG. 4 is a perspective view, viewing a motor according to theembodiment from the lower side.

FIG. 5 is a perspective view of a stator according to the embodiment.

FIG. 6 is a disassembled perspective view illustrating the stator, asensor board, and a lower lid.

FIG. 7 is a plane cross-sectional view of the blower.

FIG. 8 is an explanatory diagram illustrating a mounting arrangement ofa rotary sensor.

FIG. 9 is a partial cutaway perspective view of an exhaust air guidemember.

FIG. 10 is a partial enlarged cross-sectional view illustrating a firstguide path of the blower according to the present embodiment.

FIG. 11 is a partial enlarged cross-sectional view illustrating a secondguide path of the blower according to the present embodiment.

FIG. 12 is a plan view of moving blades of the impeller.

FIG. 13 is a side view illustrating the blower according to the presentembodiment.

FIG. 14 is a cross-sectional view illustrating an exhaust air guide hole(flow path) according to the present embodiment.

FIG. 15 is a cross-sectional view illustrating an exhaust air guide hole(flow path) according to another example.

FIG. 16 is a plane cross-sectional view of a blower according to a firstmodification.

FIG. 17 is a longitudinal-sectional view of a blower (centrifugal airblower) according to a second modification.

FIG. 18 is a plan view of a stator according to the second modification.

FIG. 19 is a plan view of a core piece according to the secondmodification.

FIG. 20 is a cross-sectional view of another example of the bloweraccording to the second modification in FIG. 17.

FIG. 21 is a perspective view illustrating a vacuum cleaner that has theblower.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A blower according to an embodiment of the present disclosure will bedescribed with reference to the drawings. Note that the scope of thepresent disclosure is not restricted to the following embodiment, andchanges may be optionally made within the scope of the technical idea ofthe present disclosure. Also note that in the drawings below, the scale,numbers, and so forth, of the structures, may be different from theactual structures, in order to facilitate understanding of theconfigurations.

Also, in the drawings, an XYZ coordinate system will be illustrated as athree-dimensional orthogonal coordinate system as appropriate. In theXYZ coordinate system, a Z-axis direction is a direction parallel to anaxial direction along a central axis J illustrated in FIG. 1. A Y-axisdirection is a direction orthogonal to the Z-axis direction and is aright-left direction in FIG. 2. An X-axis direction is a direction thatis orthogonal to both of the Y-axis direction and the Z-axis direction.

Also, in the following description, a direction (the Z-axis direction)in which the central axis J extends will be referred to as a verticaldirection. The positive side in the Z-axis direction (+Z side) will bereferred to as the “upper side (upper side in the axial direction)” andthe negative side in the Z-axis direction (−Z side) will be referred toas the “lower side (lower side in the axial direction)”. Note that thevertical direction, the upper side, and the lower side are terms thatare used simply for the purpose of description and do not limit theactual positional relationship or direction. In addition, unlessotherwise specifically noted, a direction (the Z-axis direction)parallel to the central axis J will be simply referred to as an “axialdirection”, a radial direction of which the central axis J is the centerwill be simply referred to as a “radial direction”, and acircumferential direction around the central axis J will be simplyreferred to as a “circumferential direction”.

FIG. 1 is a perspective view illustrating a blower 1 according to thepresent embodiment. FIG. 2 is a cross-sectional diagram illustrating ablower 1 according to the present embodiment. FIG. 3 is a disassembledperspective view of the blower 1 according to the present embodiment,excluding a control board 11 and board case 15.

A blower 1 includes a motor 10, an impeller 70, an exhaust air guidemember 60, an impeller housing 80, a control board 11, and a board case15, as illustrated in FIG. 1 through FIG. 3. The motor 10 has a rotor 30and stator 40, which will be described later, so the blower 1 has therotor 30, the stator 40, a housing 20, and the impeller 70.

The exhaust air guide member 60 is attached to the upper side (+Z side)of the motor 10. The impeller housing 80 is attached to the upper sideof the exhaust air guide member 60. The impeller 70 is accommodatedbetween the exhaust air guide member 60 and impeller housing 80. Theimpeller 70 is attached to the motor 10 rotatably on the central axis J.The control board 11, and the board case 15 that covers the controlboard 11, are attached on the lower side (−Z side) of the motor 10.

FIG. 4 is a perspective view, viewing a motor 10 according to thepresent embodiment from the lower side.

The motor 10 includes the housing 20, a lower lid 22, the rotor 30 thathas a shaft 31, the stator 40, a sensor board 50, a lower-side bearing52 a, and an upper-side bearing 52 b, as illustrated in FIG. 2 and FIG.4.

The housing 20 is a cylindrical covered container accommodating therotor 30 and stator 40. More specifically, the housing 20 is acylindrical form extending in the axial direction, and accommodates therotor 30 and stator 40. The housing 20 has a peripheral wall 21 that iscylindrical in shape, an upper lid portion 23 positioned at the upperend of the peripheral wall 21, and an upper-side bearing holding portion27 positioned at the middle portion of the upper lid portion 23. Thestator 40 is fixed on the inner side face of the housing 20. Theupper-side bearing holding portion 27 is a cylinder protruding towardthe upper side from the middle portion of the upper lid portion 23. Theupper-side bearing holding portion 27 holds the upper-side bearing 52 bwithin.

Multiple through holes 25 and 26 are provided at an edge portion 21 a ofthe peripheral wall 21 of the housing 20 and upper lid portion 23, asillustrated in FIG. 3. That is to say, the housing 20 has through holes25 and 26 that open to the inner side. Three through holes 25 and threethrough holes 26 are positioned alternately around the axis (see FIG.7). The through holes 25 and 26 reach from the upper side of theperipheral wall 21 to the outer edge of the upper lid portion 23. Thethrough holes 25 and 26 pass through the peripheral wall 21 in theradial direction. The through holes 25 and 26 also pass through theupper lid portion in the vertical direction near the outer edge thereofin the radial direction.

The lower lid 22 is attached to an opening at the lower side (−Z side)of the housing 20. A cylindrical lower-side bearing holding portion 22 cthat protrudes toward the lower side from the lower face of the lowerlid 22 is provided to the middle portion of the lower lid 22. Thelower-side bearing holding portion 22 c holds the lower-side bearing 52a.

The lower lid 22 is provided with through arc-shaped holes 22 a havingwidth in the radial direction, at three positions around the axis, asillustrated in FIG. 4. Notched portions 22 b where the peripheralportion of the lower lid 22 has been linearly notched are provided atthree positions on the peripheral edge of the lower lid 22. Gaps betweenthe opening end 20 a at the lower side of the housing 20 and the notchedportions 22 b are lower-side openings 24 of the motor 10.

The rotor 30 has the shaft 31, a rotor magnet 33, a lower-side magnetfixing member 32, and an upper-side magnet fixing member 34, asillustrated in FIG. 2. That is to say, the rotor 30 has the shaft 31.The rotor magnet 33 has a cylindrical shape encompassing the shaft 31around the axis (θz direction) at the outer side in the radialdirection. The lower-side magnet fixing member 32 and upper-side magnetfixing member 34 are cylindrical shapes, having an outer diameterequivalent to that of the rotor magnet 33. The lower-side magnet fixingmember 32 and upper-side magnet fixing member 34 are attached to theshaft 31, sandwiching the rotor magnet 33 from both sides in the axialdirection. The upper-side magnet fixing member 34 has a minor radiusportion 34 a that is smaller in diameter than the lower side (rotormagnet 33 side).

The shaft 31 is disposed following the central axis J that extendsvertically. The shaft 31 is rotatably supported around the axis (θzdirection) by the lower-side bearing 52 a and upper-side bearing 52 b.The impeller 70 is attached to the end of the shaft 31 at the upper side(+Z side). The impeller 70 integrally rotates with the shaft 31 on theaxis.

FIG. 5 is a perspective view of the stator 40 according to the presentembodiment. FIG. 6 is a disassembled perspective view illustrating thestator 40, sensor board 50, and lower lid 22. FIG. 7 is a planecross-sectional view of the motor 10.

The stator 40 is positioned on the outer side from the rotor 30 in theradial direction. The stator 40 encompasses the rotor 30 around the axis(θz direction). The stator 40 has a stator core 41, multiple (three)upper-side insulators 43, multiple (three) lower-side insulators 44, andcoils 42, as illustrated in FIG. 5 and FIG. 6. The stator core 41includes a core back portion 41 a and multiple teeth portions 41 b, asillustrated in FIG. 5. The stator 40 also has a molded portion (flowpath forming member) 47 in which the coils 42 are embedded. That is tosay, the stator 40 has the core back portion 41 a, teeth portions 41 b,insulators, coils 42, and flow path forming member. The insulators inthe present embodiment correspond to the upper-side insulators 43 andlower-side insulators 44. Further, the flow path forming membercorresponds to the molded portion 47.

The stator core 41 includes the ring-shaped core back portion 41 a andmultiple (three) teeth portions 41 b extending inward in the radialdirection from the core back portion 41 a, as illustrated in FIG. 6. Thecore back portion 41 a is ring-shaped around the central axis. The coreback portion 41 a has a configuration where linear portions 41 c atthree positions around the axis, and three arc portions 41 d, arealternatingly positioned. The teeth portions 41 b each extend inward inthe radial direction from the inner peripheral faces of the linearportions 41 c. The teeth portions 41 b are disposed equidistantlyfollowing the circumferential direction. Inclined members 46 that guideexhaust air to the inner side of the stator 40 are each disposed at theupper faces of arc portions 41 d of the core back portion 41 a. Theinclined members 46 each have a shape where the thickness progressivelybecomes smaller from the outer side in the radial direction toward theinner side in the radial direction.

The insulators (upper-side insulators 43 and lower-side insulators 44)cover at least part of the teeth portions 41 b. Also, the coils 42 arewound on each of the teeth portions 41 b via the insulators (upper-sideinsulators 43 and lower-side insulators 44).

The upper-side insulators 43 are insulating members covering part of theupper face and side faces of the stator core 41. The upper-sideinsulators 43 are provided corresponding to each of the three teethportions 41 b. The upper-side insulators each have an upper-side outerperipheral wall portion 43 a positioned at the upper side from the coreback portion 41 a, an upper-side inner peripheral wall portion 43 epositioned at the upper side from the tip of the teeth portion 41 b, andan upper-side insulating portion 43 d that links the upper-side outerperipheral wall portion 43 a and upper-side inner peripheral wallportion 43 e in the radial direction, and that is positioned at theupper side of a portion of the teeth portion 41 b where the coil 42 iswound.

The lower-side insulators 44 are insulating members covering part of thelower face and side faces of the stator core 41. The lower-sideinsulators 44 are provided corresponding to each of the three teethportions 41 b. The lower-side insulators each have a lower-side outerperipheral wall portion 44 a positioned at the lower side from the coreback portion 41 a, a lower-side inner peripheral wall portion 44 cpositioned at the lower side from the tip of the teeth portion 41 b, anda lower-side insulating portion 44 b that links the lower-side outerperipheral wall portion 44 a and lower-side inner peripheral wallportion 44 c in the radial direction, and that tis positioned at thelower side of a portion of the teeth portion 41 b where the coil 42 iswound.

The upper-side insulators 43 and lower-side insulators 44 sandwich theteeth portions 41 b of the stator core 41 in the vertical direction. Thecoils 42 are wound on the teeth portions 41 b covered by the upper-sideinsulating portions 43 d of the upper-side insulators 43 and thelower-side insulating portions 44 b of the lower-side insulators 44.

The three upper-side outer peripheral wall portions 43 a positionedabove the core back portion 41 a of the stator core 41 encompass thecoils 42 from the outside in the radial direction, at the upper sidefrom the stator core 41. The upper-side outer periphery wall portion 43a has a first side face 43 b and second side face 43 c at both endsthereof in the circumferential direction. The first side face 43 b is aninclined face that is inclined as to the radial direction and faces theouter side in the radial direction. The second side face 43 c is aninclined face that is inclined as to the radial direction and faces theinner side in the radial direction.

A flat face 43 f and an upper-side inclined protruding portion 43 g areprovided in tandem in the circumferential direction at a portion of theouter peripheral faces of the upper-side outer peripheral wall portion43 a positioned above the linear portion 41 c. The flat face 43 f ispositioned at a second side face 43 c side, and the upper-side inclinedprotruding portion 43 g is positioned at a first side face 43 b. Anarc-shaped face that is disposed following the inner peripheral face ofthe housing 20 is disposed between the flat face 43 f and the secondside face 43 c. Also, the outer peripheral face of the upper-sideinclined protruding portion 43 g is an arc-shaped face following theinner peripheral face of the housing 20.

The flat face 43 f extends in the axial direction, matching the outerperipheral face of the linear portion 41 c of the stator core 41.

The upper-side inclined protruding portion 43 g protrudes to the outerside in the radial direction as to the flat face 43 f. The upper-sideinclined protruding portion 43 g also protrudes toward the lower side inthe axial direction, and covers part of the linear portion 41 c of thestator core 41 from the outer side in the radial direction. Anaxial-direction flat face 43 j, and an upper-side guide inclined face 43h positioned at the lower side from the axial-direction flat face 43 j,are provided on the side face of the upper-side inclined protrudingportion 43 g that is adjacent to the flat face 43 f. The upper-sideguide inclined face 43 h gradually inclines in a direction facing thelower side the farther toward the lower side it is. The axial-directionflat face 43 j and upper-side guide inclined face 43 h are smoothlyconnected. The inclination direction of the upper-side guide inclinedface 43 h is the same direction as the rotational direction of theimpeller. Accordingly, the swirling component of exhaust air flowingthrough air flow paths FP is smoothly directed toward the lower side bythe upper-side guide inclined face 43 h and a later-described lower-sideguiding inclined face 44 h. Thus, the venting efficiency of exhaust airflowing through the air flow paths FP can be improved.

The upper-side outer peripheral wall portions 43 a that are adjacent inthe circumferential direction are separated by predetermined gaps, asillustrated in FIG. 7. At adjacent upper-side outer peripheral wallportions 43 a, the first side face 43 b of one upper-side outerperiphery wall portion 43 a and the second side face 43 c of the otherupper-side outer periphery wall portion 43 a are disposed facing eachother in the circumferential direction. The degree of inclination of thefirst side face 43 b as to the radial direction and the degree ofinclination as to the radial direction of the second side face 43 cdiffer. In further detail, the width in the circumferential direction ofan opening portion 90 at the outer side in the radial direction of a gapCL formed between adjacent upper-side outer periphery wall portions 43 ais narrower than the width in the circumferential direction of anopening portion 91 at the inner side in the radial direction.

Below the gaps CL are the inclined members 46 disposed above the coreback portion 41 a (see FIG. 6). The inclined members 46 are sandwichedbetween the first side faces 43 b and second side faces 43 c. The gapsCL are positioned on the inner side of the through holes 26 of thehousing 20. The through holes 26 and the gaps CL are air flow paths thatguide exhaust air flowing in from the outer side of the housing 20 tothe inner side of the stator 40. The direction of inclination of thegaps CL as to the radial direction as viewed from above (direction fromthe outer side toward the inner side in the radial direction) matchesthe direction of flow of exhaust air discharged from the exhaust airguide member 60 in the circumferential direction. That is to say, thismatches the rotational direction of the impeller 70.

Forming the opening portions 90 at the inlet side of the gaps CLrelatively larger than the opening portions 91 at the outlet side, asillustrated in FIG. 7 enables more exhaust air to be suctioned into thegaps CL from the through holes 26, and relatively narrowing the width ofthe opening portions 91 at the outlet side enables the air dischargedfrom the gaps CL to be caused to flow toward target positions (coils 42)more accurately.

The three lower-side outer peripheral wall portions 44 a positioned atthe lower side from the core back portion 41 a encompass the coils 42 atthe lower side of the stator core 41 from the outer side in the radialdirection, as illustrated in FIG. 6. Although there are gaps betweenlower-side outer peripheral wall portions 44 a that are adjacent in thecircumferential direction, the lower-side outer peripheral wall portions44 a may be in contact with each other in the circumferential direction.

Of the outer peripheral faces of the lower-side outer peripheral wallportions 44 a, the portions positioned at the lower side from the linearportions 41 c of the core back portion 41 a each have a flat face 44 dand a lower-side inclined protruding portion 44 g provided in tandem inthe circumferential direction. Both sides in the circumferentialdirection of the region where the flat face 44 d and lower-side inclinedprotruding portion 44 g are provided, are provided with arc-shaped facesdisposed following the inner peripheral face of the housing 20.

The flat face 44 d extends in the axial direction matching the outerperipheral face of the linear portion 41 c.

The lower-side inclined protruding portion 44 g protrudes towards theouter side in the radial direction with regard to the flat face 44 d.The lower-side inclined protruding portion 44 g also covers part of thelinear portion 41 c of the stator core 41 protruding toward the upperside in the axial direction. An axial-direction flat face 44 j, and alower-side guiding inclined face 44 h positioned at the upper side fromthe axial-direction flat face 44 j, are disposed on a side face of thelower-side inclined protruding portion 44 g adjacent to the flat face 44d. The lower-side guiding inclined face 44 h gradually inclines in adirection facing toward the upper side the closer to the upper side itis. The axial-direction flat face 44 j and lower-side guiding inclinedface 44 h are smoothly connected. The direction of inclination of thelower-side guiding inclined face 44 h is the same direction as therotational direction of the impeller.

The lower-side inclined protruding portions 44 g of the lower-sideinsulators 44 and the upper-side inclined protruding portions 43 g ofthe upper-side insulators 43 are disposed in a staggered manner in thecircumferential direction and axial direction, across gaps, asillustrated in FIG. 5. The lower-side guiding inclined faces 44 h andupper-side guide inclined faces 43 h face each other across gaps. Thegaps between the lower-side guiding inclined faces 44 h and upper-sideguide inclined faces 43 h are part of the air flow paths FP between thestator 40 and housing 20. The swirling component of exhaust air flowingthrough the air flow paths FP is smoothly directed toward the lower sideby the lower-side guiding inclined face 44 h and upper-side guideinclined face 43 h. Accordingly, the venting efficiency of exhaust airflowing through the air flow paths FP can be improved.

Multiple (two in the illustration) plate portions 45 that extend in theaxial direction are provided to each flat face 44 d. The plate portions45 are erected approximately perpendicular to the flat face 44 d. Thetips of the plate portions 45 at the outer side in the radial directionreach the inner peripheral face of the housing 20. The plate portions 45section the region of the air flow path FP between the lower-side outerperipheral wall portion 44 a and the housing 20 into multiple regions inthe circumferential direction.

The molded portion 47 functions as a flow path forming member. That isto say, the molded portion 47 configures exhaust guide holes 48 servingas flow paths. At least part of the molded portion 47 is positioned atthe inner side in the radial direction of the core back portion 41 a.The molded portion 47 is formed filling in a region of the stator 40encompassed by the upper-side outer peripheral wall portions 43 a of theupper-side insulators 43 and the lower-side outer peripheral wallportions 44 a of the lower-side insulators 44, as illustrated in FIG. 5.Accordingly, the molded portion 47 covers the coils 42. The moldedportion 47 is positioned between upper-side insulators 43, betweenlower-side insulators 44, and between coils 42, that are adjacent toeach other. That is, in other words the molded portion 47 can be said tobe connecting part of insulators or coils at one side in thecircumferential direction and part of insulators or coils at the otherside in the circumferential direction. Thus, the molded portion 47 issupported within the motor 10. The molded portion 47 reaches from theupper end of the upper-side insulators 43 to the lower end of thelower-side insulators 44. The molded portion 47 is also provided with athrough hole 47 a through which the rotor is passed. The molded portion47 encompasses and strongly supports the coils 42, and also integrallyholds the upper-side insulators 43, lower-side insulators 44, statorcore 41, and sensor board 50. Accordingly, the molded portion 47 canreduce vibrations generated from the stator 40.

The resin material of which the molded portion 47 is configured is notrestricted, as long as it has insulating properties and the coils 42 canbe covered and embedded. The molded portion 47 may also be configured ofa hot-melt material with a low melting point. In a case of configuringthe molded portion 47 from a hot-melt material, the molded portion 47can be formed using a simple mold.

Three groove-shaped exhaust guide holes (flow paths) 48 that reach fromthe upper side to the lower end are provided on the outer peripheralface of the molded portion 47. The groove-shaped exhaust guide holes 48are covered from the outer side in the radial direction by the by thecore back portion 41 a of the stator core 41, partway in the verticaldirection. That is to say, the exhaust guide holes 48 pass through theinner side of the core back portion 41 a in the radial direction. Also,at least part of the inner side face of the core back portion 41 a inthe radial direction is exposed to the exhaust guide holes 48. Thus, thecore back portion 41 a can be efficiently cooled. Note that part of thewinding wires of the coils 42, upper-side insulators 43, and lower-sideinsulators 44 may be exposed to the exhaust guide holes 48. The exhaustguide holes 48 have upper openings 48 a that open to the outer side inthe radial direction, positioned at the upper side from the core backportion 41 a, as illustrated in FIG. 2. The upper openings 48 a open tothe outer side in the radial direction. The exhaust guide holes 48 haveinclined faces 48 c that smoothly incline toward the lower side at theinner side of the upper openings 48 a in the radial direction. Theexhaust guide holes 48 also have lower openings 48 b positioned at thelower end face of the molded portion 47, that open to the lower side.The lower openings 48 b are positioned directly above the through holes22 a of the lower lid 22. That is to say, the molded portion 47 has theupper openings 48 a opening at the upper side from the core back portion41 a and the lower openings 48 b opening at the lower side from the coreback portion 41 a. The upper openings 48 a open toward the outer side inthe radial direction. Accordingly, air flowing from the outer side ofthe core back portion 41 a can be efficiently guided into the stator 40.The lower openings 48 b open toward the lower side in the axialdirection. Accordingly, air heading toward the lower side in the axialdirection can be discharged to the outer side of the housing 20 withoutchanging the direction of the air flow, by the exhaust guide holes 48formed in the axial direction. The exhaust guide holes 48 also connectthe upper openings 48 a and lower openings 48 b. Accordingly, air isefficiently guided, and the inside of the stator 40 can be cooled, bythe exhaust guide holes 48.

As illustrated in FIG. 5, the upper openings 48 a of the exhaust guideholes 48 face the three gaps CL of the first side faces 43 b and secondside faces 43 c of the upper-side insulators 43. The gaps CL areconnected to the through holes 26 of the housing 20. Accordingly, theexhaust guide holes 48 connect to the through holes 26 of the housing20. Thus, air flow paths can be configured further on the inner sidefrom the core back portion 41 a, and the inside of the stator 40 can beefficiently cooled. The width of the exhaust guide holes 48 matches thewidth of the opening portions 91 positioned on the inner side of thegaps CL in the radial direction, as illustrated in FIG. 7. Also, theexhaust guide holes 48 open from the outer peripheral face of the moldedportion 47 and extend toward the lower side, as illustrated in FIG. 2.Note however, that the width of the exhaust guide holes 48 and the widthof the opening portions 91 do not necessarily have to be the same width,and may be different widths. The molded portion 47 has first inclinedfaces 48 d and second inclined faces 48 e that make up the side walls onboth sides of the exhaust guide holes 48 in the width direction. Thefirst inclined faces 48 d consecutively continue with the first sidefaces 43 b of the upper-side insulators 43. That is to say, the firstinclined faces 48 d are positioned progressively further at the forwardside in rotational direction of the impeller 70 as to the radialdirection, the further toward the inner side in the radial direction.The second inclined faces 48 e consecutively continue with the secondside faces 43 c of the upper-side insulators 43. That is to say, thesecond inclined faces 48 e are positioned progressively further at theforward side in rotational direction of the impeller 70 as to the radialdirection, the further toward the inner side in the radial direction.Accordingly, the molded portion 47 has inclined faces at the upperopenings 48 a that are positioned in the progressively further at theforward side in rotational direction of the impeller 70 as to the radialdirection, the further toward the inner side in the radial direction.Now, these inclined faces correspond to the first inclined faces 48 dand second inclined faces 48 e. Accordingly, the exhaust air has aswirling component heading in the forward side in rotational directionof the impeller 70, so providing the first inclined faces 48 d andsecond inclined faces 48 e inclined in the rotational direction, as sidewalls making up the exhaust guide holes 48, can raise the ventingefficiency.

Exhaust air discharged from the gaps CL to the inner side of the stator40 in the radial direction is guided into the exhaust guide holes 48from the upper openings 48 a, and the direction of flow is directedtoward the lower side following the inclined faces 48 c. Further, theexhaust air passes through the interior of the exhaust guide holes 48and is discharged at the lower side of the stator 40 via the loweropenings 48 b. Providing the exhaust guide holes 48 in the moldedportion 47 enables the exhaust air flowing among the coils 42 to besmoothly discharged toward the lower side without turbulence, wherebythe venting efficiency can be raised. Note that in a case where thestator 40 does not have a molded portion 47, members having the exhaustguide holes 48 may be displaced between the coils 42. Also, the loweropenings 48 b may have a shape where the cross-sectional area of theflow path progressively increases toward the lower side, which will bedescribed alter with reference to FIG. 14. According to thisconfiguration, air passing through the exhaust guide holes 48 flows tothe lower side more smoothly, so venting efficiency can be improved.

FIG. 14 is a cross-sectional view of an exhaust guide holes 48, takenalong line XIV-XIV in FIG. 7.

The molded portion 47 has a linear portion 48 f and a tapered portion 48h positioned vertically, as side walls making up an exhaust guide hole48. The tapered portion 48 h is positioned at the lower side of thelinear portion 48 f. A boundary portion 48 g is provided between thelinear portion 48 f and tapered portion 48 h. The linear portion 48 fmakes up a linear wall face in the vertical direction. Accordingly, thecross-sectional area of the exhaust guide hole 48 does not change alongthe vertical direction in the linear portion 48 f. The tapered portion48 h is inclined as to the vertical direction, so that the opposingwalls separate from each other the further toward the lower side.Accordingly, the flow-path cross-sectional area of the exhaust guidehole 48 progressively increases from the upper side toward the lowerside at the tapered portion 48 h. Thus, according to the presentembodiment, the molded portion 47 has a tapered portion 48 h where theflow-path cross-sectional area of the exhaust guide hole 48progressively increases from the upper side toward the lower side.Accordingly, the static pressure of the exhaust air can be graduallyreduced by the time of reaching the lower opening 48 b, so occurrence ofturbulence nearby the lower openings 48 b can be suppressed, and theventing efficiency of the blower 1 can be increased.

FIG. 15 is a cross-sectional view of an exhaust guide hole 148 accordingto another example that can be employed in the present embodiment. Notethat FIG. 15 is a cross-sectional view corresponding to FIG. 14. Theexhaust guide hole 148 illustrated in FIG. 15 has the same configurationas that of the above-described exhaust guide hole 48, except for thecross-sectional shape along the vertical direction.

The molded portion 47 in the example illustrated in FIG. 15 has a firsttapered portion 148 f and a second tapered portion 148 h positionedvertically, as side walls making up an exhaust guide hole 148. Thesecond tapered portion 148 h is positioned at the lower side of thefirst tapered portion 148 f. A boundary portion 148 g is providedbetween the first tapered portion 148 f and second tapered portion 148h.

The first tapered portion 148 f is inclined as to the verticaldirection, so that the opposing walls come closer to each other thefurther toward the lower side. Accordingly, the flow-pathcross-sectional area of the exhaust guide hole 148 progressivelydecreases from the upper side toward the lower side at the first taperedportion 48 f. Thus, the molded portion 47 has a first tapered portion148 f where the flow-path cross-sectional area of the exhaust guide hole148 progressively decreases from the upper side toward the lower side.

On the other hand, the second tapered portion 148 h is inclined as tothe vertical direction, so that the opposing walls separate from eachother the further toward the lower side. Accordingly, the flow-pathcross-sectional area of the exhaust guide hole 148 progressivelyincreases from the upper side toward the lower side at the secondtapered portion 148 h. Thus, the molded portion 47 has a second taperedportion 148 h positioned at the lower side from the first taperedportion 148 f, where the flow-path cross-sectional area of the exhaustguide hole 148 progressively increases from the upper side toward thelower side.

The exhaust guide hole 148 is narrowest at the boundary portion 148 g.Air that has flowed into the exhaust guide hole 148 is narrowed down dueto increased flow-path resistance at the first tapered portion 148 f,and thereafter passes the boundary portion 148 g and flows into thesecond tapered portion 148 h. The flow-path cross-sectional areagradually increases for the air that has flowed into the second taperedportion 148 h, when heading toward the lower side. Accordingly, pressureof the air is gradually release, the flow gradually becomes gentle, anddischarge is performed without separation. Accordingly, air blowingefficiency is improved.

The sensor board 50 is disposed between the stator 40 and the lower lid22, as illustrated in FIG. 2 and FIG. 6. The sensor board 50 has acircular ring-shaped main unit portion 50 a, and three protrudingportions 50 b that protrude toward the outer side from the outer edge ofthe main unit portion 50 a, in a direction inclined as to the radialdirection. The main unit portion 50 a has a through hole through whichthe shaft 31 is passed. The sensor board 50 is fixed to the lower-sideinsulators 44.

The sensor board 50 has at least three rotary sensors 51 mountedthereupon. The rotary sensors 51 are Hall elements, for example. Thesensor board 50 may be electrically connected to the coils 42. In thiscase, a driving circuit that outputs driving signals to the coils 42 maybe mounted on the sensor board 50.

FIG. 8 is an explanatory diagram illustrating a mounting arrangement ofa rotary sensor 51.

The rotary sensors 51 are disposed interposed between tip portions oflower-side inner peripheral wall portions 44 c that are adjacent in thecircumferential direction, as illustrated in FIG. 7 and FIG. 8. Thethree rotary sensors 51 are equidistantly disposed every 120° in thecircumferential direction. The faces of the rotary sensors 51 on theinner side in the radial direction face the rotor magnet 33. The rotormagnet 33 is disposed at the center portion of the rotor 30 in the axialdirection in the case of the present embodiment. Accordingly, the rotarysensors 51 are connected to the sensor board 50 by leads 51 a of alength corresponding to the length from the sensor board 50 to the rotormagnet 33 in the axial direction.

A mechanism that supports the rotary sensors 51 may be provided to thetip portion of the lower-side inner peripheral wall portions 44 c. Forexample, recesses may be provided into which the rotary sensors 51 areinserted, thereby suppressing movement of the rotary sensors 51 in theradial direction. Alternatively, the rotary sensors 51 may be fixed tothe lower-side inner peripheral wall portions 44 c by snap-fitting orthe like.

The lower lid 22 is attached to the opening end 20 a of the housing 20accommodating the stator 40 and sensor board 50, as illustrated in FIG.4. The three through holes 22 a of the lower lid 22 are at least partlypositioned on the outer side in the radial direction from the outerperipheral end of the main unit portion 50 a of the sensor board 50, asillustrated in FIG. 2. The through holes 22 a serve as second vents 97that vent the exhaust air that has passed through the exhaust guideholes 48 of the molded portion 47 toward the lower side of the motor 10.

The notches 22 b of the lower lid 22 are disposed approximately matchingthe linear portions 41 c of the stator core 41, the flat faces 43 f ofthe upper-side insulators 43, and the flat faces 44 d of the lower-sideinsulators 44, as viewed in the axial direction. The lower-side openings24 at the lower face of the motor 10 serve as first vents 96 thatdischarge exhaust air that has passed through the air flow paths FPbetween the stator 40 and housing 20, as illustrated in FIG. 2.

Next, the exhaust air guide member 60, impeller 70, and impeller housing80 will be described.

FIG. 9 is a partial cutaway perspective view of the exhaust air guidemember 60 from below. FIG. 10 and FIG. 11 are enlarged cross-sectionalviews illustrating part of the impeller 70, exhaust air guide member 60,and impeller housing 80. Note that FIG. 10 illustrates a first guidepath D1 that will be described later, and FIG. 11 illustrates a secondguide path D2 that will be described later.

The exhaust air guide member 60 is attached to the housing 20 of themotor 10. The exhaust air guide member 60 has a disc-ring-shapedsupporting member 66 a, a ring-shaped protruding portion 66 c protrudingtoward the upper side from the outer peripheral edge of the supportingmember 66 a, a cylindrical partitioning ring 66 b extending toward thelower side from the outer peripheral edge of the supporting member 66 a,an outer periphery cylindrical portion 65 that encompasses thepartitioning ring 66 b from the outer side in the radial direction, anmultiple (six in the illustration) inner guide portions 67 extendingtoward the lower side from the lower end of the outer peripherycylindrical portion 65.

The supporting member 66 a has a cylindrical attachment ring 68 thatextends from the lower face of the middle portion toward the lower side,and three columnar protruding portions 69 that protrude from the lowerface of the supporting member 66 a toward the lower side, as illustratedin FIG. 9.

The three columnar protruding portions 69 had the same diameters andheights, and are equidistantly disposed every 120° in thecircumferential direction. The columnar protruding portions 69 arehollow in the present embodiment, and each have a protruding portionthrough hole 69 b at the middle of an end face 69 a at the lower sidethat passes through in the axial direction.

The upper-side bearing holding portion 27 of the housing 20 is insertedinto the attachment ring 68 of the exhaust air guide member 60, asillustrated in FIG. 10. The lower face of the attachment ring 68 of theexhaust air guide member 60 and the end face 69 a at the lower side ofthe columnar protruding portions 69 come into contact with the upperface of the upper lid portion 23 of the housing 20. The exhaust airguide member 60 and the motor 10 are fastened by bolts BT passed throughthe protruding portion through holes 69 b of the columnar protrudingportions 69 and screw holes 23 a in the upper lid portion 23.

The partitioning ring 66 b and outer periphery cylindrical portion 65face each other in the radial direction across a gap. The gap betweenthe partitioning ring 66 b and outer periphery cylindrical portion 65make up part of first guide paths D1 that guide exhaust air into themotor 10, and part of second guide paths D2 that discharge exhaust airto the periphery of the motor 10. The first guide paths D1 arepositioned at locations in the outer peripheral direction where theinner guide portions 67 have been provided, and the second guide pathsD2 are positioned between the inner guide portions 67 in thecircumferential direction. Six each of the first guide paths D1 andsecond guide paths D2 are provided along the circumferential directionin the present embodiment.

The multiple inner guide portions 67 each fit to the through holes 26 orthrough holes 25 of the housing 20, as illustrated in FIG. 1. The outerperipheral faces of the inner guide portions 67 extend in the axialdirection matching the outer peripheral face of the outer peripherycylindrical portion 65, as illustrated in FIG. 9 and FIG. 10. The innerperipheral faces 67 b of the inner guide portions 67 are inclined facesinclined toward the inner side in the radial direction, the furthertoward the lower side they are. The inner side of the inner peripheralfaces 67 b of the inner guide portions 67 serve as first guide paths D1to guide exhaust air discharged from the impeller 70 to the throughholes 25 and 26 at the inner side in the radial direction. The innerperipheral faces 67 b of the inner guide portions 67 also is providedwith multiple stator vanes 67 a extending in the vertical direction inthe form of ribs. The stator vanes 67 a link the partitioning ring 66 band the inner guide portion 67 in the radial direction. The exhaust airpassing through the first guide paths D1 is rectified between the statorvanes 67 a and is efficiently guided to the through holes 25 and 26.Note that the stator vanes 67 a may be included in the rotationaldirection of the impeller 70. In this case, exhaust air including theswirling component in the rotational direction of the impeller 70 can beguided to the through holes 25 and 26 even more efficiently.

The second guide paths D2 that guide exhaust air discharged from theimpeller 70 to the outer side in the radial direction and discharge tothe outer side of the motor 10 are provided between the inner guideportions 67 in the circumferential direction, as illustrated in FIG. 9.The second guide paths D2 are positioned between an outer peripheralface 66 e of the partitioning ring 66 b and an inner peripheral face 65a of the outer periphery cylindrical portion 65, as illustrated in FIG.11. Third vents 95 are provided at the lower end of the second guidepaths D2. The third vents 95 turn the exhaust air that has passedthrough the second guide paths D2 downward, and discharge to the outerside of the motor 10. This exhaust air flows between the outerperipheral face of the motor 10 and an inner peripheral face 19 a of acasing 19 that accommodates the motor 10, and finally is discharged froma later-described final vent 17 b (see FIG. 2).

The outer peripheral face 66 e of the partitioning ring 66 b has aninner-side inclined portion 66 d that progressively hangs out toward theouter side in the radial direction the closer to the lower side it is.On the other hand, the inner peripheral face 65 a of the outer peripherycylindrical portion 65 has an outer-side inclined portion 65 b where thethickness of the outer periphery cylindrical portion 65 is thinner atthe lower end. Due to these inner-side inclined portion 66 d andouter-side inclined portion 65 b being provided, the second guide pathsD2 travel to the outer side in the radial direction while maintainingthe width in the radial direction as they head toward the lower side.The cross-sectional area of the second guide paths D2 in placesperpendicular to the axial direction gradually increases the closer tothe third vents 95. Accordingly, the discharge sound of air beingdischarged from the third vents 95 can be reduced. Also, the dischargeefficiency at the time of air being discharged from the third vents 95is improved.

The impeller 70 is attached to the shaft 31 at the upper side from thestator 40. The impeller 70 discharges fluid suctioned from an intakeport 70 a that is opened toward the upper side, toward the outer side inthe radial direction via internal flow paths, as illustrated in FIG. 2.The impeller 70 has an impeller main body 71 and an impeller hub 72.

The impeller main body 71 has a base portion 73, multiple moving blades74, and a shroud 75. The base portion 73 is disc-shaped, and has athrough hole 73 a passing through in the axial direction at the middleportion. The perimeter of the through hole 73 a of the base portion 73is an inclined portion 73 b that has a conical face shape extending atthe upper side. The moving blades 74 are plate-shaped members curved inthe circumferential direction, that extend from the inner side in theradial direction toward the outer side on the upper face of the baseportion 73. The moving blades 74 are disposed erected following theaxial direction. The shroud 75 is a cylindrical shape that tapers towardthe upper side in the axial direction. An opening portion at the middleof the shroud 75 is the intake port 70 a of the impeller 70. The baseportion 73 and shroud 75 are linked by the moving blades 74.

FIG. 12 is a plan view of the moving blades 74 of the impeller 70.

The multiple moving blades 74 are disposed following the circumferentialdirection (θz direction) on the upper face of the base portion 73, asillustrated in FIG. 12. The moving blades 74 are erected perpendicularlyfrom the upper face of the base portion 73 following the axialdirection, as illustrated in FIG. 2.

In the present embodiment, three types of moving blades are disposed,with the same types of moving blades being equidistantly disposed in thecircumferential direction. The multiple moving blades 74 in the presentembodiment include multiple (three) first moving blades 74 a, multiple(three) second moving blades 74 b, and multiple (six) third movingblades 74 c. The three first moving blades 74 a are disposed atequidistantly every 120° in the circumferential direction. The secondmoving blades 74 b are each disposed between first moving blades 74 aadjacent in the circumferential direction. The three second movingblades 74 b are also disposed equidistantly every 120° in thecircumferential direction. The third moving blades 74 c are eachdisposed between first moving blades 74 a and second moving blades 74 badjacent in the circumferential direction. The six third moving blades74 c are disposed equidistantly every 60° in the circumferentialdirection.

The moving blades 74 extend on the upper face of the base portion 73having a curvature in plan view (XY plane view). One end of the movingblades 74 is positioned on an outer edge of the base portion 73. Theother end of each moving blade 74 is positioned on the inner side of theouter edge of the base portion 73 in the radial direction.

That is to say, the end portions of each of the first moving blades 74a, the second moving blades 74 b, and the third moving blades 74 c, atthe outer side in the radial direction, are all positioned on the outeredge of the base portion 73. On the other hand, end portions P1 of thefirst moving blades 74 a on the inner side are positioned closest to thecenter of the base portion 73. End portions P2 of the second movingblades 74 b on the inner side are positioned on the outer side in theradial direction from the end portions P1 of the first moving blades 74a. End portions P3 of the third moving blades 74 c on the inner side arepositioned further on the outer side in the radial direction from theend portions P2 of the second moving blades 74 b.

The first moving blades 74 a, the second moving blades 74 b, and thethird moving blades 74 c, each have a shape that is curved like a bow ina counterclockwise direction.

The first moving blades 74 a are each formed of four arcs that aredifferent in radius of curvature. A projecting blade face 74 d of thefirst moving blades 74 a has three inflection points CP11, CP12, andCP13, in the longitudinal direction.

The second moving blades 74 b are each formed of three arcs that aredifferent in radius of curvature. A projecting blade face 74 e of thesecond moving blades 74 b has two inflection points CP21 and CP22 in thelongitudinal direction.

The third moving blades 74 c are each formed of two arcs that aredifferent in radius of curvature. A projecting blade face 74 f of thethird moving blades 74 c has one inflection point CP31 in thelongitudinal direction.

In the present embodiment, the inflection point CP11 of each firstmoving blade 74 a, the inflection point CP21 of each second moving blade74 b, and the inflection point CP31 of each third moving blade 74 c, areeach disposed at the same radius position C1 on the base portion 73.Further, the radius of curvature of a portion of each first moving blade74 a that is further on the outer side of the radial position C1, theradius of curvature of a portion of each second moving blade 74 b thatis further on the outer side of the radial position C1, and the radiusof curvature of a portion of each third moving blade 74 c that isfurther on the outer side of the radial position C1, are the same aseach other.

Next, the inflection point CP12 of each first moving blade 74 a, theinflection point CP22 of each second moving blade 74 b, and the endportion P3 of each third moving blade 74 c are each disposed at the sameradius position C2 on the base portion 73. Further, the radius ofcurvature of a portion of each first moving blade 74 a that is disposedbetween the radial position C1 and the radial position C2, the radius ofcurvature of a portion of each second moving blade 74 b disposed betweenthe radial position C1 and the radial position C2, and the radius ofcurvature of a portion of each third moving blade 74 c that is disposedbetween the radial position C1 and the radial position C2, are the sameas each other.

Next, the inflection point CP13 of each first moving blade 74 a and theend portion P2 of each second moving blade 74 b are disposed at the sameradius position C3 on the base portion 73. Further, the radius ofcurvature of a portion of each first moving blade 74 a that is disposedbetween the radial position C2 and the radial position C3 and the radiusof curvature of a portion of each second moving blade 74 b disposedbetween the radial position C2 and the radial position C3 are the sameas each other.

The radius of curvature of the blade faces 74 d to 74 f of the movingblades 74 (74 a through 74 c) in the present embodiment are differentfor each region of the impeller 70 in the radial direction. Meanwhile,portions of different types of moving blades (the first moving blades 74a through third moving blades 74 c) that belong to the same region inthe radial direction are set to have the same radius of curvature.

In the present embodiment, the radial position C3 agrees with the intakeport 80 a of the impeller housing 80 as seen in the axial direction.Accordingly, only the portions of the first moving blades 74 a furtheron the inner side than the inflection point CP13 are disposed inward ofthe intake port 80 a.

The impeller hub 72 includes a cylindrical portion 72 a that extends inthe axial direction, a disc-shaped flange portion 72 b that extendsoutwards in the radial direction from the lower portion of the outerface of the cylindrical portion 72 a, and multiple projecting portions72 c that protrude upwards from the upper face of the flange portion 72b. The cylindrical portion 72 a includes a tapered inclined face portion72 d that becomes tapered toward the tip portion at the upper side.

The impeller hub 72 is attached to the impeller main body 71 byinserting the cylindrical portion 72 a into the through hole 73 a of thebase portion 73 from the lower side. The cylindrical portion 72 a may bepress-fitted into the through hole 73 a, or may be fixed using anadhesive agent or the like. The flange portion 72 b of the impeller hub72 supports the impeller main body 71 from the lower side. Theprojecting portions 72 c on the flange portion 72 b are fitted intorecesses 73 c on the lower face of the base portion 73. Fitting theprojecting portions 72 c into the recesses 73 c suppresses relativemovement of the impeller main body 71 and the impeller hub 72 in thecircumferential direction.

Due to the impeller hub 72 including the flange portion 72 b, the flangeportion 72 b can support the impeller main body 71 over a wide area inthe radial direction from below. Accordingly, the impeller 70 can beheld in a stable manner, and stability at the time of high-speedrotation is increased.

The inclined face portion 72 d at the tip of the cylindrical portion 72a of the impeller hub 72 and the inclined face portion 73 b of the baseportion 73 are smoothly connected to each other in the verticaldirection in the impeller 70. The inclined face portion 72 d and theinclined face portion 73 b make up a ring-shaped inclined face 70 b thatguides fluid suctioned from the intake port 70 a of the impeller 70 tothe outer side in the radial direction.

Configuring the ring-shaped inclined face 70 b from the impeller mainbody 71 and the impeller hub 72 enables the maximum height of thering-shaped inclined face 70 b to be increased by increasing the lengthof the cylindrical portion 72 a (inclined face portion 72 d) withoutincreasing the height of the inclined face portion 73 b of the baseportion 73. Accordingly, a ring-shaped inclined face 70 b having apreferable shape can be realized while suppressing increase in thicknessof the base portion 73.

The impeller hub 72 is preferably made of metal. In this case, the shaft31 and the impeller 70 can be strongly linked to each other.Accordingly, the impeller 70 can be rotated at high speeds in a stablemanner. Moreover, a metal face can be used as the inclined face portion72 d, and accordingly the surface of the upper tip of the ring-shapedinclined face 70 b can be smoothed.

The impeller 70 is fixed to the shaft 31 by fitting the upper endportion of the shaft 31 into the cylindrical portion 72 a of theimpeller hub 72 from the lower side. As illustrated in FIG. 2, theimpeller 70 connected to the shaft 31 is disposed at the inner side ofthe ring-shaped protruding portion 66 c of the exhaust air guide member60. Accordingly, the protruding portion 66 c is disposed nearby a vent70 c of the impeller 70.

The protruding portion 66 c guides exhaust air discharged from theimpeller 70 to the lower side, along with a later-described exhaust airguide 83 of the impeller housing 80. In the present embodiment, theouter peripheral face of the ring-shaped protruding portion 66 c is aninclined face that is inclined downwards the further on the outer sidein the radial direction it is. The outer peripheral face of theprotruding portion 66 c is a smooth convex curved face toward the outerside.

The lower end of the outer peripheral face of the protruding portion 66c is smoothly connected to the outer peripheral face of the cylindricalpartitioning ring 66 b. Accordingly, the inclination angle as to adirection perpendicular to the axial direction is approximately 90° atthe lower end of the protruding portion 66 c. The upper end of theprotruding portion 66 c is positioned on the immediately outer side inthe radial direction of the outer edge of the base portion 73 of theimpeller 70. The upper end of the protruding portion 66 c is positionedat the upper side from the lower face of the base portion 73, but ispositioned at the lower side from the upper face of the outer edge ofthe base portion 73.

In the blower 1 according to the present embodiment, air discharged fromthe impeller 70 can be smoothly guided downwards without turbulence inthe flow, due to the protruding portion 66 c having the above-describedshape and placement. At the lower end of the vent 70 c of the impeller70, air is discharged from the outer edge of the base portion 73 in adirection approximately perpendicular to the axial direction. The upperend of the protruding portion 66 c is at a position lower than the upperface of the base portion 73 in the present embodiment, so the dischargedair is guided following the other peripheral face of the protrudingportion 66 c without colliding with the protruding portion 66 c.Accordingly, air can be conveyed efficiently.

The impeller housing 80 has the intake port 80 a on the upper side, andhas the shape of a cylinder that is tapered toward the upper side in theaxial direction, as illustrated in FIG. 2. The impeller housing 80 hasan intake guide portion 81 positioned at the opening end of the intakeport 80 a, an impeller housing main body 82 that accommodates theimpeller 70, an exhaust air guide 83 extending from the outer peripheraledge of the impeller housing main body 82 toward the outer side in theradial direction and toward the lower side, in a form like a skirt, andan outer periphery attachment ring 84 that extends toward the upper sidefrom the outer peripheral edge of the exhaust air guide 83.

The impeller housing main body 82 has a cross-sectional shape modeledafter that of the shroud 75 of the impeller 70. The inner face (lowerface) of the impeller housing main body 82 faces the outer face (upperface) of the shroud 75 across a uniform spacing.

The ring-shaped intake guide portion 81 that protrudes toward the innerside in the radial direction is positioned on the upper end of the innerperipheral side of the impeller housing main body 82. The intake guideportion 81 covers an upper end face 75 b of the shroud 75 from above, asillustrated in FIG. 10. A narrow gap runs in the radial directionbetween the lower face of the intake guide portion 81 and the upper endface 75 b of the shroud 75.

A peripheral edge bend portion 82 a, bent to wrap around the outerperipheral end of the shroud 75, is provided to the end of the impellerhousing main body 82 at the outer peripheral side. The peripheral edgebend portion 82 a extends to the lower side and encompasses the outerside end face of the shroud 75 from the outer side in the radialdirection. A narrow gap extending to the upper side in the axialdirection runs between the inner peripheral face of the peripheral edgebend portion 82 a and the outer side end face of the shroud 75.

The exhaust air guide 83 makes up an exhaust air flow path 92 thatguides exhaust air, discharged to the outer side in the radial directionfrom the impeller 70, toward the lower side, as illustrated in FIG. 10and FIG. 11. The inner peripheral face of the exhaust air guide 83smoothly inclines from a direction perpendicular to the axial directiontoward the axial direction, from the upper end toward the lower end. Theinner peripheral face of the exhaust air guide 83 is gently connectedand the lower end to the inner peripheral face 65 a of the outerperipheral cylindrical portion 65 of the exhaust air guide member 60,thereby making up a wall face at the outer peripheral side of theexhaust air flow path 92.

The outer periphery attachment ring 84 is cylindrical in shape. Theouter periphery attachment ring 84 has a flange portion 84 a extendingfrom the upper end toward the outer side in the radial direction. Theouter peripheral face of the outer periphery attachment ring 84 fits tothe inner peripheral face of the outer periphery cylindrical portion 65of the exhaust air guide member 60. The flange portion 84 a also comesinto contact with the upper end of the outer periphery cylindricalportion 65 and positions the impeller housing 80 as to the exhaust airguide member 60 in the vertical direction.

A recess 86 that extends in the circumferential direction is provided onthe upper face of the exhaust air guide 83. The recess 86 is made up ofthe peripheral edge bend portion 82 a, exhaust air guide 83, and outerperiphery attachment ring 84. The thickness of the exhaust air guide 83is made uniform due to the recess 86 having been provided to theimpeller housing 80. Moreover, ribs 85 that connect the outer peripheryattachment ring 84 to the peripheral edge bend portion 82 a of theimpeller housing main body 82 in the radial direction are provided inthe recess 86.

The impeller housing 80 is produced by molding. That is to say, theimpeller housing 80 is manufactured by injecting a material in a fluidstate into a cavity between two or more molds, which is then hardened.The impeller housing 80 according to the present embodiment is made of aresin material, and is fabricated by injection molding. In a case offorming the impeller housing 80 of an aluminum alloy, the impellerhousing 80 is fabricated by aluminum die-casting. The molded articlemanufactured by molding may exhibit sink marks on the surface of thickportions, due to shrinkage when the material hardens, and this maydeteriorate dimensional precision. In the case of performing aluminumdie-casting, air pockets (cavities) may occur within thick portions, andthis may deteriorate strength.

The recess 86 is provided between the outer periphery attachment ring 84and the peripheral edge bend portion 82 a of the impeller housing mainbody 82 of the impeller housing 80 according to the present embodiment.Thus, the thickness of the exhaust air guide 83 can be made uniform inthe impeller housing 80, thereby suppressing occurrence of sink marksfrom occurring on the periphery of the exhaust air guide 83. In the sameway, air pockets can be suppressed from occurring within the exhaust airguide 83 of the impeller housing 80. Further, the ribs 85 are providedto the recess 86 of the impeller housing 80 according to the presentembodiment, so rigidity of the outer periphery attachment ring 84 as tothe impeller housing main body 82 can be increased. Accordingly, theimpeller housing 80 can be strongly fixed to the exhaust air guidemember 60 at the outer periphery attachment ring 84.

The board case 15 is attached to the lower side of the motor 10, andencompasses the control board 11, as illustrated in FIG. 1 and FIG. 2.The board case 15 has a disc-shaped base wall 16, and a cylindricalportion 17 that extends upward from the outer edge of the base wall 16.The cylindrical portion 17 is provided with the final vent 17 b thatpasses through the board case 15 in the radial direction so the innerside and the outer side communicate. The final vent 17 b merges anddischarges air discharged from the vents (first vents 96, second vents97, and third vents 95).

FIG. 13 is a side view of the motor 10.

An upper end face 17 a of the cylindrical portion 17 is inclined in aspiral form centered on the central axis J, as illustrated in FIG. 1 andFIG. 13. The upper end face 17 a progressively inclines in the samedirection as the rotation direction of the impeller 70 toward the lowerside. The final vent 17 b is positioned at the lower end side of thespiral of the upper end face 17 a. Exhaust air discharged from the thirdvents 95 of the exhaust air guide member 60 flows downwards between theouter peripheral face of the motor 10 and the inner peripheral face 19 aof the casing 19 accommodating the motor 10. Upon reaching the upper endface 17 a of the cylindrical portion 17, this exhaust air follows theincline of the upper end face 17 a, swirls and reaches the final vent 17b, and is discharged. The upper end face 17 a guides exhaust airincluding the swirling component that is discharged obliquely downwardsfrom the third vents 95 to the final vent 17 b without changing thedirection of flow at an abrupt angle, so deterioration of ventingefficiency can be reduced.

At least one third vent 95 of the multiple third vents 95 is positioneddirectly above the final vent 17 b. The third vent 95 that is positioneddirectly above the final vent 17 b will be referred to as a direct-abovevent 95A here. An uppermost end 17 c of the upper end face 17 a ispositioned at the lower side of the inner guide portion 67 in thepresent embodiment. Accordingly, exhaust air discharged from thedirect-above vent 95A is not guided to the upper end face 17 a, butrather passes over a distance that is shorter than being guided to theupper end face 17 a and is discharged from the final vent 17 b, and thuscan improve the discharge efficiency from the direct-above vent 95A.

The upper end face 17 a in the present embodiment has been exemplarilyillustrated with regard to a case where the inclination along thecircumferential direction is constant. However, the upper end face 17 amay be an inclined face of which the inclination changes along thecircumferential direction. In this case, the upper end face 17 apreferably is an inclined face where the angle of inclination graduallybecomes gentler from the upper side toward the lower side. For example,the upper end face 17 a may be a curved face that is convex toward thelower side, with the radial center of curvature of the curved face thatthe upper end face makes up being positioned at the upper side from theupper end face 17 a. Accordingly, exhaust air flowing toward the lowerside may be made to gradually swirl following the upper end face 17 a,and be guided to the final vent 17 b, whereby discharge efficiency canbe improved.

The control board 11 is connected to coil lines extending from the coils42, and the sensor board 50, and controls the motor 10. The controlboard 11 is attached to the lower side of the motor 10 in a stage ofbeing inclined as to the lower lid 22, via multiple (three in thepresent embodiment) post-shaped members 13 fixed to the lower lid 22, asillustrated in FIG. 2. The post-shaped members 13 are fixed by screwingto screw holes 22 d in the lower lid 22. The multiple post-shapedmembers 13 each have different heights. Also, inclined faces areprovided to the lower side end faces of the post-shaped members 13. Thecontrol board 11 is fixed by screwing to the lower side end faces of thepost-shaped members 13 via spacers 13 a.

The control board 11 is inclined toward the final vent 17 b of the boardcase 15, within the board case 15. That is to say, the lowest point ofthe control board 11 is positioned toward the final vent 17 b side.

Exhaust air that has passed through the interior of the motor 10 andbeen discharged to the lower side of the motor 10 from the first vents96 and second vents 97 strikes the control board 11 and cools thecontrol board 11. Further, exhaust air that has struck an upper face 11a of the control board 11 is smoothly discharged to the final vent 17 bfollowing the inclination of the control board 11. That is to say,venting efficiency can be increased due to the control board 11 beinginclined toward the final vent 17 b. Further, the projection area of thecontrol board 11 as viewed from the axial direction can be reduced bydisposing the control board 11 in an inclined manner. Accordingly, thegap between the outer edge of the control board 11 and the innerperipheral face of the cylindrical portion 17 of the board case 15 canbe increased to let exhaust air flow to a lower face 11 b side of thecontrol board 11. Accordingly, even in a case where mounted parts thatgenerate a great amount of heat, such as capacitors or the like, aremounted on the lower face 11 b of the control board 11, these can beefficiently cooled.

The position of the control board 11 in the axial direction preferablyis close, within a range where there is no interference between theupper face 11 a of the control board 11 and the mounted parts mounted onthe upper face 11 a, and the lower lid 22 of the motor 10. Accordingly,not only is the cooling efficiency of the control board 11 improved, butalso the effect of the exhaust air being guided to the final vent 17 bdue to the inclination of the control board 11 can be increased.

The blower 1 according to the present embodiment draws air onto theimpeller 70 from the intake port 80 a by rotating the impeller 70 by themotor 10, and discharges air to the outer side in the radial directionvia air flow paths within the impeller 70, as illustrated in FIG. 2. Theexhaust air discharged from the impeller 70 passes through the exhaustair flow path 92 and flows into the exhaust air guide member 60. Theexhaust air flow path 92 is positioned between the inner peripheral faceof the exhaust air guide 83 of the impeller housing 80 and the outerperipheral face of the protruding portion 66 c, and directs exhaust air,discharged toward the outer side in the radial direction by the impeller70, toward the lower side. The exhaust air flowing toward the lower sideof the exhaust air flow path 92 is branched into and flows through firstguide paths D1 and second guide paths D2 alternately positioned in thecircumferential direction of the exhaust air guide member 60.

Exhaust air passing through the first guide paths D1 is guided furtherto the inner side in the radial direction than the inner peripheral face67 b of the inner guide portion 67, and is rectified by the stator vanes67 a and flows to the interior of the motor 10 through the through holes25 and 26, as illustrated in FIG. 10.

The exhaust air that has flowed into the interior of the motor 10 viathe through holes 25 flows into the air flow paths FP between the stator40 and housing 20 illustrated in FIG. 7. The exhaust air flows towardthe lower side in the air flow paths FP. The upper-side inclinedprotruding portions 43 g of the upper-side insulators 43 and thelower-side inclined protruding portions 44 g of the lower-sideinsulators 44 direct the swirling component of the exhaust air towardthe lower side within the air flow paths FP, as illustrated in FIG. 5.The outer peripheral faces of the linear portions 41 c (stator core 41)are exposed within the air flow paths FP, and are cooled by the exhaustair. Multiple plate portions 45 are disposed within the air flow pathsFP, and rectify the exhaust air flowing through the air flow paths FP.Exhaust air that has passed through the air flow paths FP is dischargeddownwards from the lower-side openings 24 serving as the first vents 96.

The exhaust air that has flowed into the motor 10 via the through holes26 flows to the inner side of the stator 40 via the gaps CL asillustrated in FIG. 7. The first side faces 43 b and second side faces43 c and inclined members 46 encompassing the gaps CL guide the exhaustair passing through the gaps CL to the exhaust guide holes 48 of themolded portion 47. According to this configuration, the coils 42, whichare heat generators in the motor 10, can be cooled. In addition, theexhaust air can be efficiently guided toward the lower side by theexhaust guide holes 48 of the molded portion 47. The exhaust airdischarged toward the lower side from the exhaust guide holes 48 isdischarged downwards from the through holes 22 a serving as the secondvents 97.

The exhaust air discharged from the first vents 96 and second vents 97strikes the upper face 11 a of the control board 11 fixed in an inclinedmanner and cools the control board 11, and further is guided toward tothe final vent 17 b of the board case 15 following the upper face 11 aof the control board 11 and is discharged.

On the other hand, exhaust air passing through the second guide paths D2moves to the outer side in the radial direction due to the inner-sideinclined portion 66 d of the partitioning ring 66 b, and is dischargedto the lower side via the third vents 95, as illustrated in FIG. 11. Theexhaust air discharged to the lower side from the third vents 95 flowstoward the lower side following the outer peripheral face of the housing20 of the motor 10. Part of the exhaust air that flows along the outerperipheral face of the housing 20 swirls in spiral form following theupper end face 17 a of the board case 15, and is guided to the finalvent 17 b and discharged, as illustrated in FIG. 13. Due to the upperend face 17 a being included in a direction matching the rotationaldirection of the impeller 70, the exhaust air that is discharged fromthe third vents 95 and that includes the swirling component in therotational direction of the impeller 70 and be efficiently guided to thefinal vent 17 b following the outer peripheral face of the motor 10.Part of the exhaust air flowing along the outer peripheral face of thehousing 20 passes over a distance shorter than having been guided by theupper end face 17 a, and reaches the final vent 17 b without passingover the upper end face 17 a, and is discharged.

Next, a blower 301 having a hollow member (flow path forming member) 347instated of the molded portion 47 in the above-described embodiment,will be described as a first modification with reference to FIG. 16.Components that are of the same form as in the above-describedembodiment are denoted by the same reference symbols, and descriptionthereof will be omitted.

A stator 340 of the blower 301 has multiple (three) hollow members (flowpath forming member) 347. The hollow members 347 are U-shaped with across-section taken at a plane orthogonal to the central axis opens tothe outer side in the radial direction, with the inner side of theU-shape being hollow. The hollow members 347 are positioned on the innerside of the core back portion 41 a in the radial direction. The hollowmembers 347 are positioned between coils 42 arrayed in thecircumferential direction. The hollow members 347 make up exhaust guideholes (flow paths) 348 extending in the vertical direction at the innerside of the core back portion 41 a in the radial direction.

The hollow members 347 according to the present modification aredisposed by inserting preformed resin materials between coils 42 arrayedin the circumferential direction. According to the present modification,the hollow members 347 can easily configure the exhaust guide holes 348extending in the axial direction. Accordingly, the blower 301 can coolthe interior of the motor 10 via the hollow members 347, and can raisedischarge efficiency.

A second modification of the above-described embodiment will bedescribed with reference to the drawings.

FIG. 17 is a longitudinal-sectional view of a centrifugal air blower(blower) 1001 according to the second modification. This centrifugal airblower 1001 is a turbo-type centrifugal fan that suctions air fromabove, from suction holes provided on an upper portion, and dischargesdownwards. Turbo-type centrifugal fans are more efficient and less noisyas compared to sirocco centrifugal fans.

The centrifugal air blower 1001 according to the present modification isprovided to a canister-type vacuum cleaner, for example, and is used togenerate suction force for the vacuum cleaner. Note however, that thecentrifugal air blower according to the present disclosure may be usedin usages other than vacuum cleaners. For example, the centrifugal airblower according to the present disclosure may be installed in other airblowers such as air supply/exhaust devices used as range hood fans orducts in buildings, home electrical appliances, medical equipment,industrial large-scale facilities, and so forth, to perform suction andexhaust.

The centrifugal air blower 1001 includes a motor 1011, an impeller 1012,and a blower casing 1013, as illustrated in FIG. 17. A later-describedrotating portion (rotor) 1030 of the motor 1011 and the impeller 1012rotate entered on a central axis 1009. The motor 1011 has the rotatingportion (rotor) 1030 and a stationary portion 1020. The stationaryportion 1020 further includes a stator 1021. The blower casing 1013 hasa lower-side casing (housing) 1135. That is to say, the centrifugal airblower 1001 has the rotor 1030, stator 1040, lower-side casing (housing)1135, and impeller 1012.

The lower-side casing 1135 accommodates the rotating portion 1030 andstationary portion 1020. A middle casing 1134 is positioned at the upperside of the lower-side casing 1135. The lower-side casing 1135 has acylindrical shape extending in the axial direction and opening at theupper side. That is to say, the lower-side casing 1135 has a throughhole that passes through the upper side in the vertical direction andopens to the inner side. The through hole of the lower-side casing 1135connects to alter-described gap 1090.

The motor 1011 is an inner-rotor type brushless DC motor. The motor 1011has the stationary portion 1020 and rotating portion (rotor) 1030. Thestationary portion 1020 is stationary in relation to the blower casing1013. The rotating portion 1030 is rotatably supported as to thestationary portion 1020, centered on the central axis 1009.

The stationary portion 1020 has the stator 1021, a motor cover 1022, abase plate 1023, a circuit board 1024, an upper bearing 1025, and alower bearing 1026. The rotating portion 1030 has a shaft 1031 and arotor 1032.

The stator 1021 generates magnetic flux in accordance with drivingvoltage supplied from the circuit board 1024. The stator 1021 isdisposed at the periphery of the later-described rotor 1032. The stator1021 has multiple core pieces 1060, multiple insulators 1070, andmultiple coils 1080.

The core pieces 1060 are disposed in a ring form around the central axis1009. The core pieces 1060 have a core back 1061 extending in thecircumferential direction, and teeth 1062 that protrude from the coreback 1061 toward the inner side in the radial direction. The insulators1070 are attached to the core pieces 1060. The coils 1080 are configuredof conducting wires wound around the teeth 1062 via the insulators 1070.Further detailed structures of the stator 1021 will be described later.

The motor cover 1022 is a resin member that holds the stator 1021. Themotor cover 1022 an upper plate portion 1221, a side plate portion 1222,a first fixing portion 1223, a second fixing portion 1224, and at leastone base plate fixing portion 1225.

The upper plate portion 1221 is a plate-shaped member that extendsgenerally perpendicular to the central axis 1009 above the stator 1021.A through hole is formed at the generally middle portion of the upperplate portion 1221. The upper bearing 1025 is held in this through holein the upper plate portion 1221. The side plate portion 1222 is agenerally cylindrical shape, and extends from the edge of the upperplate portion 1221 downward in the axial direction.

The base plate fixing portion 1225 protrudes toward the outer side inthe radial direction from around the lower end portion of the side plateportion 1222. At least one screw hold is formed in the base plate fixingportion 1225. Base plate fixing portions 1225 are provided at threepositions in the circumferential direction in the motor 1011 accordingto the present modification. Note however, that the number of positionsof fixing the motor cover 1022 and base plate 1023 is not restricted tothree positions, and may be two positions, or four positions or more.Also, the motor cover 1022 and base plate 1023 may be fixed by othermethods, such as adhesion, crimping, or the like. The structures of thefirst fixing portion 1223 and second fixing portion 1224 will bedescribed later.

The base plate 1023 is a member covering at least part of the loweropening of the motor cover 1022. The base plate 1023 extends generallyperpendicular to the central axis 1009. A recess is formed at the middleof the base plate 1023. The lower bearing 1026 is held in this recess inthe base plate 1023. The stator 1021, circuit board 1024, upper bearing1025, lower bearing 1026, and rotor 1032, are accommodated in theinterior of a casing configured of the motor cover 1022 and base plate1023.

The circuit board 1024 is generally plate shaped in the presentmodification. The circuit board 1024 is positioned generallyperpendicular to the central axis 1009, further toward the lower sidethan the stator 1021. Electronic parts making up an electric circuit forsupplying driving current to the coils 1080 are mounted on the circuitboard 1024. The ends of conducting wires making up the coils 1080 areelectrically connected to the electric circuit on the circuit board1024.

The upper bearing 1025 rotatably supports the shaft 1031 as to the motorcover 1022. The lower bearing 1026 rotatably supports the shaft 1031 asto the base plate 1023. Ball bearings, where ball-shaped rolling membersare interposed between an inner ring and an outer ring, are used for theupper bearing 1025 and lower bearing 1026, for example. An elasticmember 1027 is interposed between the motor cover 1022 and the upperbearing 1025. Accordingly, the vibration when the motor 1011 andimpeller 1012 rotate is reduced. Note that bearings of types other thanball bearings may be used for the upper bearing 1025 and lower bearing1026.

The shaft 1031 is disposed along the vertically-extending central axis1009. More specifically, the shaft 1031 is a post-shaped member disposedalong the central axis 1009. The shaft 1031 is supported by the upperbearing 1025 and lower bearing 1026, and can rotate centered on thecentral axis 1009. The upper end of the shaft 1031 protrudes further tothe upper side than the motor cover 1022. The impeller 1012 is directlyfixed at the upper end of the shaft 1031. Although the impeller 1012 isfixed at the upper end of the shaft 1031 in the present modification,the impeller 1012 may be indirectly fixed to the shaft 1031, via anothermember such as a cylindrical member made of a resin material or metalmaterial, or the like.

The rotor 1032 is fixed to the shaft 1031, and rotates centered on thecentral axis 1009 along with the shaft 1031. The rotor 1032 according tothe present modification is made of a magnetic resin formed in agenerally cylindrical shape. The outer peripheral face of the rotor 1032is magnetized with N poles and S poles alternately in thecircumferential direction. The outer peripheral face of the rotor 1032faces the end face of the teeth 1062 at the inner side in the radialdirection, across a minute gap. That is to say, the rotor 1032 hasmagnetic faces facing the stator 1021 in the radial direction.

Note that although a rotor 1032 made of magnetic resin is used in thepresent modification, the rotor 1032 may be an arrangement wheremultiple magnets are fixed on the outer peripheral face or the inside ofa cylindrical rotor core that is a magnetic material.

When driving the motor 1011, driving current is supplied to the coils1080 from a power source via the electric circuit on the circuit board1024, and magnetic fluxes are generated at the multiple teeth 1062.Accordingly, torque is generated on the circumferential direction die tothe magnetic fluxes acting between he teeth 1062 and rotor 1032. As aresult, the rotating portion 1030 rotates centered on the central axis1009. The impeller 1012 also rotates along with the rotation of therotating portion 1030.

The impeller 1012 is a so-called turbo-type centrifugal impeller. Theimpeller 1012 is disposed above the motor cover 1022 of the motor 1011.The impeller 1012 has an upper shroud 1051, a lower shroud 1052, andmultiple blades 1053, as illustrated in FIG. 17.

The upper shroud 1051 includes a cylindrical portion 1511, a sleeveportion 1512, and a suction port 1513. The upper shroud 1051 is disposedabove the lower shroud 1052 and multiple blades 1053.

The cylindrical portion 1511 is a generally cylindrical member centeredon the central axis 1009. The cylindrical portion 1511 according to thepresent modification has a diameter that is generally constantregardless of the position in the axial direction. Note that thecylindrical portion 1511 may have a shape where the diameterprogressively increases toward the lower side in the axial direction.

The sleeve portion 1512 expands toward the outer side in the radialdirection from the lower end of the cylindrical portion 1511. The radialposition of the outer edge of the sleeve portion 1512 is generally thesame as the position of the outer edge of the lower shroud 1052 in theradial direction. The suction port 1513 is positioned at the middle ofthe upper shroud 1051. The suction port 1513 is formed of thecylindrical portion 1511 and passes in the axial direction through theupper shroud 1051 at the inner side of the cylindrical portion 1511 inthe radial direction.

The lower shroud 1052 is a plate-shaped member that extends generallyperpendicular to the central axis 1009, above the motor cover 1022. Thelower face of the lower shroud 1052 facings the upper face of the motorcover 1022 in the axial direction. The tip on the inner side in theradial direction of the lower shroud 1052 is fixed to the shaft 1031 ofthe motor 1011.

The blades 1053 are disposed between the upper shroud 1051 and the lowershroud 1052 in the axial direction. The multiple blades 1053 aredisposed generally equidistantly in the circumferential direction. Whendriving the centrifugal air blower 1001, gas between the upper shroud1051 and lower shroud 1052 is accelerated to the outer side in theradial direction by the multiple blades 1053.

An upper-side casing 1133 has a top plate portion 1131 and a wallportion 1132. The top plate portion 1131 is positioned above theimpeller 1012, and extends in a ring shape following the upper face ofthe upper shroud 1051. The top plate portion 1131 has a middle hole 1130at the middle thereof. The middle hole 1130 is connected to theabove-described suction port 1513. The wall portion 1132 extendsdownwards in a cylindrical form from the top plate portion 1131 at theouter side of the motor 1011 in the radial direction. At least the upperend of the motor 1011 and the impeller 1012 are accommodated on theinner side of the wall portion 1132 in the radial direction. That is tosay, the wall portion 1132 encompasses at least part of the motor 1011.The inner side face of the wall portion 1132 faces at least part of themotor 1011 in the radial direction.

The blower casing 1013 according to the present modification is formedfrom three ring-shaped members, which are the upper-side casing 1133,middle casing 1134, and lower-side casing 1135. The middle casing 1134is disposed beneath the upper-side casing 1133. The lower-side casing1135 is disposed beneath the middle casing 1134. The upper-side casing1133 includes the upper end of the top plate portion 1131 and wallportion 1132. The middle casing 1134 and lower-side casing 1135 arecylindrical members forming the wall portion 1132. The blower casing1013 according to the present modification has been described as beingformed of three members, but the blower casing 1013 may be formed of onemember, or may be formed of two, or four or more members. That is tosay, the blower casing 1013 is formed of at least one member.

The outer peripheral face of the motor cover 1022 and the innerperipheral face of the wall portion 1132 of the blower casing 1013 aredisposed across a gap in the radial direction. The gap between the outerperipheral face of the motor cover 1022 and the inner peripheral face ofthe wall portion 1132 serves as a flow path 1010 of gas when driving thecentrifugal air blower 1001. At least part of the flow path 1010connects to a vent that the wall portion 1132 has.

A communication hole 1100 that connects the outside and inside of themotor cover 1022 is formed in the motor cover 1022 in this space orbelow this space in the axial direction, the communication hole 1100communicating with a gap (flow path) 1090.

The gap 1090 has a generally triangular shape or generally trapezoidalshape in plan view. The gap 1090 is positioned on the inner side of thecore back 1061 in the radial direction. The gap 1090 has an upperopening 1090 a positioned at the upper side of the core back 1061, and alower opening 1090 b positioned at the lower side of the core back 1061.The upper opening 1090 a opens toward the upper side in the axialdirection. the lower opening 1090 b opens toward the lower side in theaxial direction. Thus, air can be efficiently guided from the upperopening 1090 a toward the lower opening 1090 b. The width of the gap1090 in the circumferential direction progressively decreases toward theinner side in the radial direction. Accordingly, the flow speed of theair flow passing through the region of the gap 1090 at the inner side onthe radial direction becomes fast, so the cooling effect is high even ifthe amount of air supplied is small. Also, a great amount of air canpass through the region of the gap 1090 at the outer side in the radialdirection, so cooling effects are high. The gap 1090 may be connected toa through hole 1221 a provided to the upper plate portion 1221 of themotor cover 1022 and pass through in the vertical direction, not onlybeing connected to the communication hole 1100. In this case, the flowof exhaust air passing through the gap 1090 becomes smooth, and ventingefficiency can be increased.

When driving the centrifugal air blower 1001, driving current issupplied to the stator 1021 of the motor 1011, and the rotating portion1030 of the motor 1011 and the impeller 1012 rotate. When the impeller1012 rotates, gas above the upper-side casing 1133 is suctioned via themiddle hole 1130 of the upper-side casing 1133 and the suction port 1513of the impeller 1012, passes between the upper shroud 1051 and lowershroud 1052, and is discharged to the outer side of the impeller 1012 inthe radial direction, as indicated by the solid arrows in FIG. 17.

The gas discharged to the outer side of the impeller 1012 in the radialdirection strikes against the wall portion 1132 of the upper-side casing1133 and changes direction downwards and toward the inner side in theradial direction, and advances downwards in the axial direction throughthe flow path 1010 formed between the outer peripheral face of the motorcover 1022 and inner peripheral face of the wall portion 1132, and thegap 1090 of the stator 1021, as illustrated FIG. 17. This air flow thenis discharged to the outside of the centrifugal air blower 1001 via avent at the lower end of the flow path 1010.

Next, a more detailed structure of the stator 1021 will be described.FIG. 18 is a plan view of the stator 1021. The stator 1021 according tothe present modification has three core pieces 1060, three insulators1070, and three coils 1080, as illustrated in FIG. 18. Thisconfiguration enables the number of times of applying electricity to thewinding wires per rotation to be reduced, so the motor is readily drivenat high speeds. Note however, that in the present disclosure, the statormay be configured from a single core piece.

Note that the insulators 1070 each have a teeth insulating portion 1071,an inner-side wall portion 1072, and an outer-side wall portion 1073.

FIG. 19 is a plan view of a core pieces 1060. The multiple core pieces1060 are formed of a magnetic material, and disposed in thecircumferential direction. Laminated steel plates, where magnetic steelplates that are magnetic material have been laminated in the axialdirection, for example, are used for the core pieces 1060. Each corepiece 1060 has a core back (core back portion) 1061 and tooth (teethportion) 1062, as illustrated in FIG. 19. The core back 1061 extends inthe outer side from the tooth 1062 in the circumferential direction.Note however, that the top view of the core back 1061 does notnecessarily have to be an arc shape, as long as the entirety extendsroughly in the circumferential direction. The tooth 1062 protrudes fromthe middle of the core back 1061 in the circumferential direction towardthe inner side in the radial direction.

The core back 1061 according to the present modification has a middlecore back portion 1611 and a pair of connecting core back portions 1612.The middle core back portion 1611 extends generally perpendicular to thetooth 1062 that extends in the radial direction. The middle core backportion 1611 also extends in both sides in the circumferential directionfrom the outer-side end of the tooth 1062 in the radial direction. Thepair of connecting core back portions 1612 is positioned on both sidesof the middle core back portion 1611 in the circumferential direction.Each connecting core back portion 1612 extends from the end of themiddle core back portion 1611 in the circumferential direction whilebending in a direction drawing closer to the tooth 1062.

This, one tooth 1062 is provided to each of the three core pieces 1060in the present modification. Accordingly, the number of teeth 1062 thatthe stator 1021 has is the minimal three for a three-phase synchronousmotor. Reducing the number of teeth 1062 enables the number of times ofswitching of the motor driving circuit per rotation to be reduced.Accordingly, the motor 1011 can be readily made to handle high speeds.

The three core pieces 1060 are arrayed in the circumferential direction,as illustrated in FIG. 18. The core backs 1061 of the three core pieces1060 are linked into a ring shape. Specifically, the edge portions ofconnecting core back portions 1612 of adjacent core pieces 1060 arelinked to each other. The joints between the core pieces 1060 are fixedby welding, for example.

A fixing hole 1063 that passes through in the axial direction isprovided to the core back 1061 of each core piece 1060. That is to say,all of the core pieces 1060 each have a fixing hole 1063 in the presentmodification. According to this configuration, all of the core pieces1060 can be firmly fixed to the motor cover 1022 at the time ofassembling the centrifugal air blower 1001. The fixing hole 1063 ispositioned on the outer side of the teeth portion 1602 in the radialdirection. The vicinity of the core back 1061 in the circumferentialdirection is a position where the magnetic flux density is low whendriving the motor 1011, and the role as a flux path is small. Providingthe fixing hole 1063 at this position suppresses the fixing hole 1063from narrowing the flux path.

The motor cover 1022 and core pieces 1060 are fixed by a fixing memberinserted into the fixing holes 1063. The motor cover 1022 has threefirst fixing portions 1223 and three second fixing portions 1224, asillustrated in FIG. 17. The three first fixing portions 1223 eachprotrude to the inner side in the radial direction from the side plateportion 1222, above the above-described fixing holes 1063. The secondfixing portions 1224 protrude toward the inner side in the radialdirection from the side plate portion 1222, below the above-describedfixing holes 1063. The first fixing portions 1223 and second fixingportions 1224 are each provided with a screw hole extending in the axialdirection. When manufacturing the motor 1011, a screw 1043, which is afixing member, is inserted into the screw hole of the second fixingportion 1224, the fixing hole 1063, and the first fixing portion 1223,at each of the three positions in the circumferential direction.Accordingly, the stator 1021 and motor cover 1022 are fixed. The motorcover 1022 and core pieces 1060 can be firmly fixed by thisconfiguration.

Note that the number of fixing positions of the stator 1021 and motorcover 1022 does not necessarily have to be three. For example, anarrangement may be made where the fixing hole 1063 is provided to onlyone or two core pieces 1060 of the three core pieces 1060. Also, eachcore piece 1060 may be provided with two or more fixing holes. Themethod of fixing the stator 1021 and motor cover 1022 may be other thanscrewing. For example, the motor cover 1022 may be resin molded with thestator 1021 as an insertion part, thereby fixing the stator 1021 andmotor cover 1022.

Now, the coils 1080 are covered at the outer peripheral faces thereof bya covering portion (flow path forming member) 1081. The covering portion1081 is resin. The coils 1080 are wound on the teeth 1062 of the stator1021, and the insulation of the coils 1080 is ensured by the coils 1080being covered by the covering portions 1081, and also vibration andnoise can be reduced.

The core pieces 1060 according to this modification has thin laminatedsteel plates laminated to reduce eddy current when rotating at highspeeds, and the strength of the laminated steel plates can be ensured bythe coils 1080 being covered by the covering portion 1081.

In addition, the gap 1090 is formed between a covering portion 1081covering a coil 1080 and a covering portion 1081 covering anotheradjacent coil 1080 in the circumferential direction. Accordingly, thecovering portions 1081 configure the gap 1090. Thus, a wind flow pathcan be provided between adjacent teeth 1062, and the stator 1021 can becooled by the air flowing through this flow path, while satisfyingairflow properties of the centrifugal air blower. The covering portions1081 may have a configuration of connecting part of an insulator 1070 orcoil 1080 at one side in the circumferential direction with an insulator1070 or coil 1080 at the other side in the circumferential direction. Inthis case, the surface area of the covering portions 1081 exposed to thegap 1090 can be increased, and the coils can be efficiently cooled viathe covering portions 1081. Note that an example is described in thismodification regarding a centrifugal air blower where three core pieces1060 are employed, so space between adjacent teeth is readily securedand the stator is easier to cool as compared to six core pieces, forexample.

Note that the distance in the circumferential direction between onecovering portion 1081 and another covering portion 1081 is longer at theupper side in the axial direction of the teeth 1062 than at the middlein the axial direction, and is longer at the lower side in the axialdirection of the teeth 1062 than at the middle in the axial direction.This static pressure of the centrifugal air blower 1001 can be raisedeven higher.

In addition, the covering portions 1081 are formed by molding.

Although description has been made in the above modification regarding acentrifugal air blower used in a canister type vacuum cleaner, this isnot restrictive. FIG. 20 illustrates a centrifugal air blower 1001A usedin a stick-type or handy-type vacuum cleaner. The stator 1021 the sameas in the above modification is used in the centrifugal air blower 1001Aas well, and the same advantages can be obtained. Thus, the presentdisclosure is applicable to a centrifugal air blower that blows airthrough a smaller diameter flow path as well.

A structure equivalent to the above modification may also be applied toa motor used for usages other than a vacuum cleaner.

Although description has been made regarding an example where the numberof core pieces is three in the above modification, the number may betwo, or may be four or more.

FIG. 21 is a perspective view of a vacuum cleaner 100 having the blower1 according to the present embodiment. The vacuum cleaner 100 has theblower according to the above-described embodiment and modifications.Accordingly, the blower 1 installed in the vacuum cleaner 100 can beefficiently cooled, and venting efficiency can be improved. Note thatthe blower according to the embodiment and modifications is notrestricted to the vacuum cleaner 100, and can be installed in otherelectric equipment as well.

Although an embodiment and modifications of the present disclosure havebeen described, the configurations and combinations thereof and so forthin the embodiment and modifications are exemplary, and additions,omissions, substitutions, and other changes may be made to theconfigurations, without departing from the essence of the presentdisclosure. The present disclosure is not restricted by embodiments.

Features of the above-described preferred embodiments and themodifications thereof may be combined appropriately as long as noconflict arises.

While preferred embodiments of the present disclosure have beendescribed above, it is to be understood that variations andmodifications will be apparent to those skilled in the art withoutdeparting from the scope and spirit of the present disclosure. The scopeof the present disclosure, therefore, is to be determined solely by thefollowing claims.

1-12. (canceled)
 13. A blower, comprising: a rotor that has a shaftdisposed following a central axis extending vertically; a statorpositioned at an outer side of the rotor in a radial direction; acylindrical housing extending in the axial direction, that accommodatesthe rotor and the stator; and an impeller attached to the shaft, at anupper side from the stator; wherein the stator includes a ring-shapedcore back portion, a plurality of teeth portions extending from the coreback portion toward an inner side in the radial direction, an insulatorthat covers at least part of the teeth portions, a coil wound on each ofthe teeth portions via the insulator, and a flow path forming member ofwhich at least part is positioned further at an inner side in the radialdirection than the core back portion, wherein the housing has a throughhole that opens to the inner side, wherein the flow path forming memberconnects part of the insulator or the coil at one side in thecircumferential direction and part of the insulator or the coil atanother side in the circumferential direction, and forms a flow paththat passes further at an inner side in the radial direction than thecore back portion, and wherein the flow path connects to the throughhole of the housing.
 14. The blower according to claim 13, wherein atleast part of an inner side face of the core back portion in the radialdirection is exposed to the flow path.
 15. The blower according to claim13, wherein the flow path forming member has an upper opening that opensto an upper side of the core back portion, and a lower opening thatopens to a lower side of the core back portion, and wherein the flowpath connects the upper opening and the lower opening.
 16. The bloweraccording to claim 13, wherein the flow path forming member covers thecoil.
 17. The blower according to claim 15, wherein the lower openingopens toward a lower side in the axial direction.
 18. The bloweraccording to claim 17, wherein the upper opening opens toward an upperside in the axial direction.
 19. The blower according to claim 17,wherein the upper opening opens toward the outer side in the radialdirection.
 20. The blower according to claim 19, wherein the flow pathforming member has an inclined face that is positioned progressivelyfurther at a forward side in rotational direction of the impeller as tothe radial direction, the further toward the inner side in the radialdirection of the upper opening.
 21. The blower according to claim 13,wherein the flow path forming member is a hollow member positionedbetween the coils arrayed in the circumferential direction.
 22. Theblower according to claim 13, wherein the flow path forming member has atapered portion where a flow path cross-sectional area progressivelyincreases from the upper side toward the lower side.
 23. The bloweraccording to claim 13, wherein the flow path forming member has a firsttapered portion where the flow path cross-sectional area progressivelydecreases from the upper side toward the lower side, and a secondtapered portion, positioned at the lower side of the first taperedportion, where a flow path cross-sectional area progressively increasesfrom the upper side toward the lower side.
 24. A vacuum cleaner,comprising the blower according to claim 13.